Evaporative Cooler and Method for Controlling the Same

ABSTRACT

An evaporative cooler includes a first heat exchanger, a first coolant storage, a second coolant storage, and a first airflow drive. The first heat exchanger is capable of cooling a coolant flowing through the first heat exchanger, and cooling an air flowing through the first heat exchanger by way of the cooled coolant. The first coolant storage forms a first coolant circulating path with the first heat exchanger and provides the coolant to the first heat exchanger. The second coolant storage forms a second coolant circulating path with the first coolant storage and is capable of supplementing the first coolant storage with the coolant. The capacity of the second coolant storage is larger than that of the first coolant storage. The first airflow drive cooperates with the first heat exchanger to direct and eject the air flowing through the first heat exchanger.

CROSS REFERENCE TO RELATED APPLICATION

The present invention claims priority to China Patent Application No. 202110819553.X filed on 20 July, 2021 with the title of “Evaporative Cooler and Method for Controlling the Same”, the entire contents of which are incorporated herein for all purposes by this reference.

TECHNICAL FIELD

The present invention relates to evaporative coolers, and more particularly, to an evaporative cooler with high cooling efficiency and low humidity, and a method for controlling the same.

BACKGROUND ART

An evaporative cooler has a cooling effect and generally includes a housing, a motor, and a fan driven by the motor. A water tank and a water curtain are provided in the housing, and a water pump is provided in the water tank to pump room-temperature water from the water tank to a location above the water curtain where the water is evaporated to absorb heat, so that the ambient temperature drops. After this, the motor drives the fan to rotate, the cooled air is then blown out of the housing, so as to achieve the cooling effect.

Typically, the current evaporative cooler bears a water tank of a large capacity to meet the requirements of cooling duration, and the room temperature of the water in the water tank limits the cooling effect even after heat exchange, with still a large room to enhance. Secondly, in a high-humidity environment, the air around the water curtain is almost saturated with water vapor, and it’s getting even harder for the water to pass through the water curtain to further evaporate. As a result, a temperature difference between an outlet and an inlet is minimal, and cooling effect is not desirable.

The above knowledge is intended merely to provide more information of the general background of the invention and should not be taken as an acknowledgment or any suggestion that such information constitutes prior art known to those of ordinary skill in the art.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an evaporative cooler with high cooling efficiency and low humidity which can solve the problem of poor cooling effect of the evaporative cooler in the prior art.

To this end, the present invention provides an evaporative cooler including a first heat exchanger, a first coolant storage, a second coolant storage, and a first airflow drive. The first heat exchanger is capable of cooling a coolant flowing through the first heat exchanger, and cooling an air flowing through the first heat exchanger by way of the cooled coolant. The first coolant storage forms a first coolant circulating path with the first heat exchanger and provides the coolant for the first heat exchanger. The second coolant storage forms a second coolant circulating path with the first coolant storage and is capable of supplementing the first coolant storage with the coolant. The capacity of the second coolant storage is larger than that of the first coolant storage. The first airflow drive is fitted with the first heat exchanger to direct and eject the air flowing through the first heat exchanger.

In an embodiment, the first coolant storage has a far smaller capacity than that of the second coolant storage for the purpose that the smaller the amount of coolant in circulation, the easier the temperature of the coolant can be dropped in a shorter time.

In one or more embodiments, the second coolant storage, the first heat exchanger, and the first coolant storage are sequentially communicated to form the circulating path.

In one or more embodiments, the first coolant storage is disposed above the second coolant storage, and the first coolant storage is provided with an overflow port communicating with the second coolant storage.

In one or more embodiments, the first coolant storage has a water level sensor assembly configured therein, and the second coolant storage has a first pump configured thereon, the first pump being controllable to turn on or off a supply of the coolant to the second coolant storage according to a sensing signal sent by the water level sensor assembly.

In one or more embodiments, the water level sensor assembly includes a low-water-level sensor provided within the first coolant storage, and the second coolant storage delivers the coolant to the first coolant storage if the low-water-level sensor sends a low-water-level sensing signal.

In one or more embodiments, the water level sensor further includes a high-water-level sensor provided in the first coolant storage, the high-water-level sensor is disposed above the low-water-level sensor, and the second coolant storage stops delivering the coolant to the first coolant storage when the high-water-level sensor sends a high-water-level sensing signal.

In one or more embodiments, a semiconductor cooling component is provided within the first coolant storage for cooling coolant therein.

In one or more embodiments, an outer side of the first coolant storage is partially wrapped with an heat insulating layer.

In one or more embodiments, a second pump is provided between the first coolant storage and the first heat exchanger for driving the coolant to circulate from and to the first heat exchanger and the first coolant storage.

In one or more embodiments, a low-water-level sensor is configured in the second coolant storage, and when the amount of the coolant in the second coolant storage is low, the low-water-level sensor sends a low-water-level sensing signal to remind a user of adding more coolant.

In one or more embodiments, the evaporative cooler further includes a housing having a chamber therein and an inlet and an outlet communicating with the chamber thereon, a first airflow passage being formed between the inlet and the outlet, and the first heat exchanger being disposed in the first airflow passage.

In one or more embodiments, the evaporative cooler further includes a second heat exchanger and a second airflow drive, wherein a coolant circulating path is formed between the second heat exchanger and the first coolant storage, and the second airflow drive is fitted with the second heat exchanger to direct and eject the air flowing through the second heat exchanger.

In one or more embodiments, a second airflow passage is also formed within the chamber and capable of directing at least part of the air cooled by the second heat exchanger into the first airflow passage.

In one or more embodiments, an air valve is provided within the second airflow passage for controlling an opening degree of the second airflow passage.

In one or more embodiments, the second airflow passage directs the air cooled by the second heat exchanger to an upstream of the first airflow drive.

In one or more embodiments, a third airflow passage is further formed in the chamber. The second heat exchanger is disposed in the third airflow passage, and the water vapor and air that have been heat exchanged in the second heat exchanger can be discharged out of the chamber through the third airflow passage.

In one or more embodiments, the evaporative cooler further includes a dehumidifier configured in the first airflow passage, the dehumidifier is disposed upstream and/or downstream of the first heat exchanger in a direction along the first airflow passage from the inlet to the outlet. The dehumidifier positioned upstream dehumidifies the air blown to the first heat exchanger, and the dehumidifier positioned downstream dehumidifies the air cooled by the first heat exchanger.

In one or more embodiments, the dehumidifier is a semiconductor dehumidifier or an adsorbent dehumidifier.

The present invention further provides a method for controlling the evaporative cooler, including: providing, by the first coolant storage, the coolant for the first heat exchanger in operation.

In one or more embodimentss, the second coolant storage supplements the first coolant storage with the coolant when a water level in the first coolant storage is lower than a preset level.

The invention also provides a method for controlling the evaporative cooler. In a first mode, operating the first heat exchanger and the first airflow drive. When the coolant in the first coolant storage flows through the first heat exchanger, the air flowing through the first heat exchanger is cooled to a first cooling temperature by the coolant through the first heat exchanger and is then ejected from the outlet, and the coolant is cooled to the first cooling temperature at the first heat exchanger.

In a second mode, operating the first heat exchanger and the first airflow drive while operating the second heat exchanger and the second airflow drive. When the coolant of the first cooling temperature flows through the second heat exchanger, the air flowing through the second heat exchanger is cooled to a second cooling temperature by the coolant of the first cooling temperature through the second heat exchanger and is then directed into the first airflow passage to increase a volume of the air ejected from the outlet and/or drop the temperature of the air ejected from the outlet; and/or the air flowing through the second heat exchanger is cooled to the second cooling temperature by the second heat exchanger by using the coolant of the first cooling temperature and then directed to the third airflow passage to be ejected.

The present invention also provides a method for controlling the evaporative cooler, wherein either the side of the inlet or the side of the outlet of the first heat exchanger is provided, respectively, with a first dehumidifier and a second dehumidifier, the first dehumidifier and the second dehumidifier being semiconductor dehumidifiers; the method includes: controlling either the first dehumidifier or the second dehumidifier to work or controlling both the first dehumidifier and the second dehumidifier to work simultaneously.

The evaporative cooler according to the present invention is more advantageous than the traditional one in that the coolant in the second coolant storage of a large capacity is input into the first coolant storage of a small capacity in advance. Meanwhile, the semiconductor cooling component is provided in the first coolant storage so that the coolant can be rapidly cooled when circulating between the first heat exchanger and the first coolant storage and the air that have been heat exchanged by the first heat exchanger has its temperature dropping faster when blown out from the outlet. In addition, the second coolant storage of the large capacity can supplement the first coolant storage of the small capacity when the coolant therein is insufficient so that the stable operation of the system is ensured.

According to the evaporative cooler of the present invention, the configuration of the first heat exchanger and the second heat exchanger makes sure that the coolant is subjected to cooling multiple times in the circulating path, which further drops the temperature of the air from the outlet and improves the cooling efficiency.

According to the evaporative cooler of the present invention, the dehumidifiers are provided both upstream and downstream of the first heat exchanger to make sure that the air flowing through the first heat exchanger is dehumidified multiple times so that the cooling effect of the evaporative cooler in a high-humidity environment is improved and low-temperature and low-humidity air can be generated at the outlet.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an evaporative cooler according to an embodiment of the present invention.

FIG. 2 is a schematic view showing a structure of a semiconductor cooling sheet according to an embodiment of the present invention.

FIG. 3 is a schematic block diagram of an evaporative cooler according to another embodiment of the present invention.

FIG. 4 is a schematic block diagram of an evaporative cooler according to yet another embodiment of the present invention.

FIG. 5 is a schematic block diagram of an evaporative cooler according to still another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, but it should be understood that the scope of the present invention is not limited to the specific embodiments.

Unless otherwise expressly stated, throughout the specification and claims, the term “comprise” or its variations such as “comprises” and “comprising” will be understood to include the stated elements or components and not exclude other elements or other components.

As shown in FIG. 1 , an embodiment of the present invention provides an evaporative cooler 100 including a housing 10, a first heat exchanger 20, a first coolant storage 30, a second coolant storage 40, and a first airflow drive 50.

The housing 10 generally forms an overall appearance of the evaporative cooler 100, and includes, for example, a front panel, a rear panel, side panels, and a ceiling, which together enclose an outer contour defining the housing 10 and an inner chamber. In addition, physical structures such as a control panel, a portable handle, and a chassis with rollers can be provided as required. The control panel can be connected to a circuit or a control component inside the evaporative cooler 100, hence an operator can adjust or set functions of the evaporative cooler 100, which will be described in the embodiments below. Other alternative physical structures on the housing 10 are not described in detail herein as they do not relate to the inventive aspects of the present application.

A chamber is formed inside the housing 10 for accommodating the first coolant storage 30, the first heat exchanger 20, the second coolant storage 40, and the first airflow drive 50. The housing 10 is provided with an inlet 11 and an outlet 12 which are in fluid communication with the chamber, and a first airflow passage P1 is formed between the inlet 11 and the outlet 12.

It is to be noted that the housing 10, and the first coolant storage 30, the first heat exchanger 20, the second coolant storage 40 and the first airflow drive 50 shown in the drawings of the present invention are not to limit the evaporative cooler 100 for practical production, but merely to illustrate how the evaporative cooler 100 cooperates with each of the components.

It should be noted that the first airflow passage P1 is not physically defined here, in other words, the first airflow passage P1 is not strictly separated or limited from anywhere else in the chamber. It’s only intended that an airflow passage exists in the chamber to direct air from the outside into the chamber through the inlet 11 of the housing 10 and out of the chamber through the outlet 12 of the housing 10, thereby forming a complete air circulation.

The first coolant storage 30 is configured for storing a coolant, such as water. The second coolant storage 40 is also adapted to store a coolant, such as water. A circulating path is formed between the first coolant storage 30 and the second coolant storage 40, and the capacity of the second coolant storage 40 is larger than that of the first coolant storage 30.

The evaporative cooler 100 may include a first pump 60 for driving the coolant in the second coolant storage 40 to circulate between the second coolant storage 40 and the first coolant storage 30.

Specifically, a high-water-level sensor 31 and a low-water-level sensor 32 are provided in the first coolant storage 30, and the high-water-level sensor 31 is disposed above the low-water-level sensor 32. The first pump 60 is in signal connection with the high-water-level sensor 31 and the low-water-level sensor 32 and can be controlled to turn on or off the delivery of the coolant from the second coolant storage 40 according to a sensing signal sent by the water level sensor. That is to say, when the low-water-level sensor 32 sends a low-water-level sensing signal, the first pump 60 is turned on, and the second coolant storage 40 delivers coolant to the first coolant storage 30; when the high-water-level sensor 31 sends a high-water-level sensing signal, the first pump 60 is turned off, and the second coolant storage 40 stops delivering the coolant to the first coolant storage 30.

The evaporative cooler 100 may further include a second pump 70 for driving the coolant in the first coolant storage 30 to circulate between the first heat exchanger 20 and the first coolant storage 30. The coolant undergoes sensible heat exchange or latent heat exchange in different heat exchange modules (the first heat exchanger 20 herein) so that the cooled air is ejected from the outlet 12.

In a specific example, the second coolant storage 40 may be carried on the chassis, and a water level mark or the like may be provided accordingly in the second coolant storage 40 to observe the water level in the second coolant storage 40. The first coolant storage 30 is disposed above the second coolant storage 40, a semiconductor cooling component 33 is provided in the first coolant storage 30 and used for cooling the coolant in the first coolant storage 30. The first coolant storage 30 is provided with an overflow port communicating with the second coolant storage 40.

In a typical cooling mode of the present embodiment, how the evaporative cooler 100 cools the air to be ejected will be described in detail below.

When the evaporative cooler 100 is in operation, the first coolant storage 30 supplies the first heat exchanger 20 with the coolant. When the water level in the first coolant storage 30 is lower than a preset level, the low-water-level sensor 32 sends a low-water-level sensing signal, and the second coolant storage 40 supplements the first coolant storage 30 with the coolant.

The semiconductor cooling component 33 operates to continuously cool the coolant in the first coolant storage 30.

The first heat exchanger 20 is configured in the first airflow passage P1 and in fluid communication with the first coolant storage 30, to cool the coolant flowing therethrough; the coolant is subjected to heat exchange at the first heat exchanger 20, has a temperature drop, and gets stored in the first coolant storage 30. The first heat exchanger 20 can cool the air flowing therethrough by using the coolant cooled by the semiconductor cooling component 33. Since the coolant has been cooled in the semiconductor cooling component 33 in advance, it is possible for such a coolant to provide higher heat exchange efficiency at the first heat exchanger 20 than a coolant not cooled yet, thereby improving the cooling capacity of the evaporative cooler.

In one embodiment, the first airflow drive 50 integrally drives the air inside the housing 10 to form an airflow, which generally has a substantially constant flow direction because of an imbalance of air pressure at the inlet 11 and the outlet 12, so that the airflow may define the above-mentioned first airflow passage P1. The first airflow drive 50 is also used to provide the kinetic energy for ejecting the air out of the outlet 12. In a physical position, the first airflow drive 50 may cooperate with the first heat exchanger 20 to direct the air flowing through the first heat exchanger 20 to the outlet 12 where it is ejected. In an embodiment, the first airflow drive 50 may be a fan provided in the first airflow passage P1.

The semiconductor cooling component 33 can be a semiconductor cooling sheet, and the semiconductor cooling sheet generally includes a plurality of negative semiconductors and positive semiconductors which are connected in series at intervals. As shown in FIG. 2 , when an electric current passes through the semiconductor cooling sheet, electrons in the negative semiconductors move downwards under the action of an electric field and release heat in aggregation with positive charges of a power supply at a lower end of the negative semiconductors; electron holes in the positive semiconductors move downwards under the action of the electric field and release heat in aggregation with negative charges of the power supply at the lower end; at the same time, the electrons and the electron holes are separated at an upper end, when heat is absorbed. As such, the semiconductor cooling component generally has a cold end and a hot end opposite the cold end. In the application of the semiconductor cooling sheet, the cold end of the semiconductor cooling sheet can be used for cooling the coolant that flows therethrough.

In the above embodiment, an outer side of the first coolant storage 30 is partially wrapped with an heat insulating layer, wherein the heat insulating layer is void where the hot end of the semiconductor cooling component 33 is located.

Referring to FIG. 3 , another embodiment of the evaporative cooler 100 of the present invention is shown. In this embodiment, the second fluid storage 40 is sequentially communicated with the first heat exchanger 20 and the first fluid storage 30 to form a circulating path.

The evaporative cooler 100 also includes a first pump 60 and a second pump 70, wherein the first pump 60 is used for driving the coolant from the second coolant storage 40 to the first heat exchanger 20; the coolant is cooled by the first heat exchanger 20, flows into the first coolant storage 30, and is then driven into the first heat exchanger 20 again by the second pump 70. The first heat exchanger 20 cools the air flowing therethrough using the cooled coolant.

Also, the first coolant storage 30 is provided with the high-water-level sensor 31 and the low-water-level sensor 32 therein, the first pump 60 is in signal connection with the high-water-level sensor 31 and the low-water-level sensor 32, and the first pump 60 is controllable to turn on or off the delivery of the coolant from the second coolant storage 40 according to the sensing signal sent by the water level sensor. That is to say, when the low-water-level sensor 32 sends a low-water-level sensing signal, the first pump 60 is turned on, and the coolant is delivered from the second coolant storage 40 to the first heat exchanger 20. When the high-water-level sensor 31 sends a high-water-level sensing signal, the first pump 60 is turned off, and the second coolant storage 40 stops delivering the coolant to the first heat exchanger 20.

Referring to FIG. 4 , another embodiment of the evaporative cooler 100 of the present invention is shown. In this embodiment, a second heat exchanger 80 and a second airflow drive 81 are further provided between the first heat exchanger 20 and the first coolant storage 30. The second heat exchanger 80 is in fluid communication with the first heat exchanger 20 and the first coolant storage 30, and the coolant cooled by the first heat exchanger 20 can be further cooled when flowing through the second heat exchanger 80.

The second heat exchanger 80 can also cool the air flowing therethrough by using the coolant cooled by the first heat exchanger 20 and can supplement with the air cooled by the second heat exchanger 80 when the evaporative cooler 100 needs greater cooling capacity and air capacity. In particular, a second airflow passage P2 is also formed in the chamber of the housing 10 and can direct at least part of the air cooled by the second heat exchanger 80 into the first airflow passage P1. The second airflow passage P2 may be defined physically, and an opening degree of the second airflow passage P2 can be controlled by an air valve 82. As such, the air valve 82 controls the amount of the airflow in the second airflow passage P2 by adjusting the opening degree, thereby regulating the amount of the air supplied to the first airflow passage P1.

The second airflow drive 81 may be a blower that may provide a force for driving the air to flow along the second airflow passage P2. In terms of to which a position of the first airflow passage P1 will the second airflow passage P2 directs the air, in this embodiment, in the direction along the first airflow passage P1 from the inlet 11 to the outlet 12, the second airflow passage P2 directs the air cooled by the second heat exchanger 80 to a position upstream of the first airflow drive 50. Surely, in some alternative embodiments, the second airflow passage P2 may also direct the cooled air directly to the outlet 12, which avoids the first airflow passage P1, moreover, the second airflow passage P2 may also be provided with an independent airflow drive to effect regulation of the volume and velocity of the air through the outlet.

A third airflow passage P3 is also formed in the chamber of the housing 10, and the second heat exchanger 80 and the second airflow drive 81 are disposed in the third airflow passage P3; the third airflow passage P3 can discharge the air subjected to heat exchange by the second heat exchanger 80 and water vapor out of the chamber.

In this embodiment, the invention also provides a method for controlling the evaporative cooler 100, which provides two working modes of the evaporative cooler 100, the method including:passing air through the evaporative cooler 100; and switching the evaporative cooler 100 between a first mode and a second mode to change a temperature and/or a volume of the air ejected from the outlet 12.

In the first mode, the first heat exchanger 20 and the first airflow drive 50 operate, the coolant in the first coolant storage 30 flows through the first heat exchanger 20, and the air flowing through the first heat exchanger 20 is cooled to a first cooling temperature by the first heat exchanger 20 by using the coolant and is then ejected from the outlet 12. Besides, the coolant is cooled to the first cooling temperature at the first heat exchanger 20; and

In the second mode, while the first heat exchanger 20 and the first airflow drive 50 are operating, the second heat exchanger 80 and the second airflow drive 80 operate as well. The coolant of the first cooling temperature cooled by the first heat exchanger 20 flows through the second heat exchanger 80, and the air flowing through the second heat exchanger 80 is cooled to a second cooling temperature by the second heat exchanger 80 by using the coolant of the first cooling temperature and is then partially directed into the first airflow passage P1 to increase a volume of the air ejected from the outlet 12 and/or drop the temperature of the air ejected from the outlet 12. The rest of the cooled air is directed into the third airflow passage P3 and ejected (an inlet and an outlet are also possible on both ends of the third airflow passage P3, and they may be arranged above or below the inlet 11 and the outlet 12 of the first airflow passage P1 on the housing 10).

Referring to FIG. 5 , another embodiment of the evaporative cooler 100 of the present invention is shown. In this embodiment, a dehumidifier 90 is further provided. The dehumidifier 90 is disposed in the first airflow passage P1 and upstream and/or downstream of the first heat exchanger 20 in the direction along the first airflow passage P1 from the inlet 11 to the outlet 12. The upstream dehumidifier 90 dehumidifies the air blown to the first heat exchanger 20, and the downstream dehumidifier 90 dehumidifies the air cooled by the first heat exchanger 20.

The dehumidifier 90 and a lower part of the first heat exchanger 20 can be further provided with a reservoir 91 for containing the coolant cooled by the first heat exchanger 20 and condensed water from the air flowing through the dehumidifier 90. The reservoir 91 is in fluid communication with the second heat exchanger 80 or the first coolant storage 30.

In an embodiment, the second airflow passage P2 may also direct the cooled air to a position between the downstream dehumidifier 90 and the first airflow drive 50.

Alternatively, the second airflow passage P2 directs the air cooled by the second heat exchanger 80 to a position between the first heat exchanger 20 and the downstream dehumidifier 90. That is to say, the air introduced into the first airflow passage P1 by the second airflow passage P2 skips the first heat exchanger 20 but is subjected to dehumidification by the dehumidifier 90.

In this embodiment, the invention also provides a method for controlling the evaporative cooler 100, which provides three other working modes of the evaporative cooler 100, the method including: passing air through the evaporative cooler 100; and switching the evaporative cooler 100 from and to a third mode, a fourth mode, and a fifth mode to change the humidity of the air ejected from the outlet 12.

In the third mode, only the upstream dehumidifier 90 is operating so that the air is dehumidified to a first humidity after flowing through the upstream dehumidifier 90 and is ejected from the outlet 12 after being cooled by the first heat exchanger 20;

In the fourth mode, only the downstream dehumidifier 90 is operating so that the air that is heat exchanged by the first heat exchanger 20 is dehumidified to a second humidity after flowing through the downstream dehumidifier 90 and is ejected from the outlet 12.

In the fifth mode, both the upstream dehumidifier 90 and the downstream dehumidifier 90 are initiated. The upstream dehumidifier 90 performs primary dehumidification on the high-humidity and high-heat airflow entering from the inlet 11, which is then cooled by the first heat exchanger 20, dehumidified again by the downstream dehumidifier 90 to a third humidity, and is finally ejected from the outlet. The dehumidifier 90 and the first heat exchanger 20 can be arranged near or close to the outlet 12 so that the cooled air can reach the outlet 12 through the shortest first airflow passage P1, with minimal dissipation of the coolness.

The dehumidifier 90 can be a semiconductor cooling dehumidifier and includes a semiconductor cooling sheet, a radiator and a heat dissipation blower which are configured cooperatively. In the dehumidification application of the semiconductor cooling sheet, the cold end of the semiconductor cooling sheet is used for condensing and dehumidifying the air flowing therethrough, and the radiator and the heat dissipation blower cooperate with a hot end of the semiconductor cooling sheet to dissipate heat from the hot end.

It should be noted that the third mode, the fourth mode, and the fifth mode relate to modes of different dehumidification intensities, and in each of them, both the first mode and the second mode are available for the adjustment of the volume and temperature of the air for the evaporative cooler.

In the above embodiment, when the ambient air humidity reaches more than 80%, the evaporative cooler 100 reaches its maximum power in the third mode and renders good dehumidifying and cooling effects. Therefore, the upstream dehumidifier 90 can be connected to a humidity sensing sensor, and when the humidity sensing sensor detects that the humidity of the ambient air reaches 80% or more, the upstream dehumidifier 90 can be controlled to start automatically; alternatively, a user can start the upstream dehumidifier 90 by himself/herself with a remote controller or a control panel external to it. When the user feels that the humidity of the cold air blown out of the outlet is high (higher than 90%), he/she may adjust and control the evaporative cooler 100 by himself/herself to start the fourth mode, that is, the downstream dehumidifier 90 is started, and the dehumidifying effect is proper. When the ambient air humidity reaches about 80% and the user feels that the humidity of the cold air blown out of the outlet is high (higher than 90%), the evaporative cooler 100 operates in the fifth mode, and the dehumidifying and cooling effects are proper.

In the embodiments/examples described above, both the first heat exchanger 20 and the second heat exchanger 80 may be a heat exchanger with a wet curtain paper. The second heat exchanger 80, the first heat exchanger 20, the dehumidifier 90, the first airflow drive 50, the second airflow drive 81, the air valve 82, the second pump 60, the second pump 70, and the like in the evaporative cooler 100 can be regulated and controlled in some functions, for example, with a built-in controller, and a user can regulate the functions of cooling and discharging airflows as required, for example, in conjunction with a receiver, a remote controller, an integrated control panel and the like. Herein, the controller may be an integrated circuit including a micro controller unit (MCU), and it is well known to those skilled in the art that an MCU may include a central processing unit (CPU), a read-only memory (ROM), a random-access memory (RAM), a timing module, an A/D converter, and several input/output ports. Of course, the controller may take the form of other integrated circuits, such as Application Specific Integrated Circuits (ASICs) or Field Programmable Gate Arrays (FPGAs).

In an embodiment of the invention, the capacity of the first coolant storage is set to be 2 L, the capacity of the second coolant storage is set to be 30 L, the evaporative cooler of the invention and an ordinary market available evaporative cooler (having only a large-capacity coolant storage) are placed in a laboratory, at a temperature of 35° C. and under a humidity of 40%, and started simultaneously, and a temperature sensing device is placed at an outlet of each of them. In 1 minute, the temperature at the outlet of the evaporative cooler of the invention is dropped to 29° C. as the lowest record, while that of the ordinary market available evaporative cooler is dropped to 32° C. as the lowest record. In 3 minutes, the temperature at the outlet of the evaporative cooler of the invention is dropped to 28° C. as the lowest record, while that of the ordinary market available evaporative cooler is dropped to 30° C. as the lowest record. In time, the temperature at the outlet of the evaporative cooler of the invention keeps around 28.5° C. , while that of the ordinary market available evaporative cooler keeps around 30.5° C.

It can be seen that in the case of a conventional evaporative cooler, the temperature at the outlet can only be dropped by 4-5° C. in stable operation, however, in the case of the evaporative cooler of the invention, the temperature at the outlet drops quickly since it is started and finally drops by 6-7° C. in stable operation, which means the present invention realizes a faster temperature drop at the outlet in a shorter time.

An exemplary workflow for the evaporative cooler 100 of the present invention is described below.

After the evaporative cooler 100 is powered on and started, the first pump 60 pumps the coolant from the second coolant storage 40 to the first coolant storage 30, the coolant is preliminarily cooled by the semiconductor cooling component 33, the second pump 70 pumps the coolant from the first coolant storage 30 to the first heat exchanger 20 to cool the air, and the first airflow drive 50 directs the cooled air to the outlet 12 to be blown out through the first airflow passage P1.

On the first heat exchanger 20, the air from the inlet 11 passes through the first heat exchanger 20 that is wet then, the coolant (water) evaporates and absorbs the heat of the ambient air so that the air is cooled and the heat of the coolant so that the coolant is cooled, and the cooled coolant enters the second heat exchanger 80.

The second heat exchanger 80 cools the air flowing therethrough by using the cooled coolant and further cools the coolant at the same time, the second airflow drive 81 directs part of the cooled air to the first airflow passage P1 or the outlet 12 through the second airflow passage P2, and the air valve 82 can adjust an opening angle as required. The second airflow drive 81 discharges the other part of the water vapor to the outside through the third airflow passage P3.

If the amount of the coolant in the first coolant storage 30 is large, the coolant flows into the second coolant storage 40 through the overflow port.

When the amount of the coolant in the first coolant storage 30 is extremely low, the low-water-level sensor 32 sends a detection signal to the controller which controls the first pump 60 to be turned on and supplements the system with the coolant in the second coolant storage 40.

When the semiconductor cooling dehumidifier is powered on and starts operation, ambient air with high humidity and high heat firstly passes through the low-temperature semiconductor cooling dehumidifier located at the upstream, part of water vapor in the air is liquefied on the semiconductor cooling dehumidifier and flows into the reservoir 91; meanwhile, the temperature of the air drops, the air passes through again the first heat exchanger 20 for heat exchange, the temperature drops again, and the air passes through the semiconductor cooling dehumidifier located at the downstream again; part of the water vapor in the air also becomes water on the component, flows into the reservoir 91, and low-temperature and low-humidity air is finally blown to the user through the outlet 12 to make the user feel cool.

The evaporative cooler disclosed by the invention is more advantageous than the prior art in that the coolant in the second coolant storage of a large capacity is input into the first coolant storage of a small capacity in advance, and meanwhile, the semiconductor cooling component is provided in the first coolant storage so that the coolant can be rapidly cooled when circulating between the first heat exchanger and the first coolant storage and the air subjected to heat exchange by the first heat exchanger has its temperature dropping faster when blown out from the outlet; moreover, the second coolant storage of the large capacity can supplement the first coolant storage of the small capacity when the coolant therein is insufficient so that the stable operation of the system is ensured.

In the evaporative cooler of the invention, the configuration of the first heat exchanger and the second heat exchanger makes sure that the coolant is subjected to cooling multiple times in the circulating path, which further reduces the temperature of the air from the outlet and improves the cooling efficiency.

In the evaporative cooler of the invention, the dehumidifiers are provided both upstream and downstream of the first heat exchanger to make sure that the air flowing through the first heat exchanger is dehumidified multiple times so that the cooling effect of the evaporative cooler in a high-humidity environment is improved and low-temperature and low-humidity air can be generated at the outlet.

The foregoing description of specific exemplary embodiments of the invention is provided for illustrative and exemplary purposes. This description is not intended to limit the invention to the details disclosed, and it's apparent that many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described to explain the principles of the invention and the practical application thereof so that those skilled in the art can implement and use the various exemplary embodiments of the invention with various alternatives and modifications. It is intended that the scope of the invention be defined only by the claims and their equivalents. 

What is claimed is:
 1. An evaporative cooler, comprising: a first heat exchanger capable of cooling a coolant flowing through the first heat exchanger, and capable of cooling an air flowing through the first heat exchanger by way of the cooled coolant; a first coolant storage forming a first coolant circulating path with the first heat exchanger and providing the coolant to the first heat exchanger; a second coolant storage forming a second coolant circulating path with the first coolant storage and capable of supplementing the first coolant storage with the coolant, the second coolant storage having a larger capacity than that of the first coolant storage; and a first airflow drive cooperating with the first heat exchanger to direct and eject the air flowing through the first heat exchanger.
 2. The evaporative cooler according to claim 1, wherein the second coolant storage, the first heat exchanger, and the first coolant storage are sequentially in communication with one another to form a thirdcoolant circulating path.
 3. The evaporative cooler according to claim 1, wherein the first coolant storage is disposed above the second coolant storage, and the first coolant storage is provided with an overflow port communicating with the second coolant storage.
 4. The evaporative cooler according to claim 1, wherein the first coolant storage has a water level sensor assembly configured therein, and the second coolant storage has a first pump configured thereon, the first pump being controllable to turn on or off a supply of the coolant to the second coolant storage according to a sensing signal sent by the water level sensor assembly.
 5. The evaporative cooler according to claim 4, wherein the water level sensor assembly includes a low-water-level sensor provided within the first coolant storage.
 6. The evaporative cooler according to claim 5, wherein the water level sensor further comprises a high-water-level sensor provided within the first coolant storage, the high-water-level sensor being disposed above the low-water-level sensor.
 7. The evaporative cooler according to claim 1, wherein a semiconductor cooling component is provided within the first coolant storage.
 8. The evaporative cooler according to claim 1, wherein an outer side of the first coolant storage is wrapped with a heat insulating layer.
 9. The evaporative cooler according to claim 1, wherein a second pump is provided between the first coolant storage and the first heat exchanger.
 10. The evaporative cooler according to claim 1, further comprising a housing having a chamber therein and an inlet and an outlet communicating with the chamber thereon, a first airflow passage being formed between the inlet and the outlet, wehrein the first heat exchanger is disposed in the first airflow passage.
 11. The evaporative cooler according to claim 10, further comprising: a second heat exchanger forming a fourth coolant circulating path with the first coolant storage, and a second airflow drive cooperating with the second heat exchanger to direct and eject the air flowing through the second heat exchanger.
 12. The evaporative cooler according to claim 11, wherein a second airflow passage is further formed within the chamber and capable of directing at least part of the air cooled by the second heat exchanger into the first airflow passage.
 13. The evaporative cooler according to claim 12, wherein an air valve for controlling an opening degree of the second airflow passage is provided in the second airflow passage.
 14. The evaporative cooler according to claim 12, wherein a third airflow passage is further formed in the chamber, the second heat exchanger is disposed in the third airflow passage, and wherein, the water vapor and air that have been heat exchanged in the second heat exchanger can be discharged out of the chamber through the third airflow passage.
 15. The evaporative cooler according to claim 10, further comprising a dehumidifier provided on a side of the inlet and/or a side of the outlet of the first heat exchanger.
 16. The evaporative cooler according to claim 15, wherein the dehumidifier is a semiconductor dehumidifier or an adsorbent dehumidifier.
 17. A method for controlling the evaporative cooler according to claim 1, comprising: in operation, the first coolant storage provides the coolant for the first heat exchanger.
 18. The method according to claim 17, wherein the second coolant storage supplements the first coolant storage with the coolant when a water level in the first coolant storage is lower than a preset level.
 19. A method for controlling the evaporative cooler according to claim 1, comprising: in a first mode, operating the first heat exchanger and the first airflow drive, and guiding and ejecting, by the first airflow drive, the air flowing through the first heat exchanger; and in a second mode, operating the first heat exchanger and the first airflow drive, and guiding and ejecting, by the first airflow drive, the air flowing through the first heat exchanger; operating the second heat exchanger and the second airflow drive, and guiding and ejecting, by the second airflow drive, the air flowing through the second heat exchanger. 